DebugInfo: Drop rest of DIDescriptor subclasses

Delete the remaining subclasses of (the already deleted) `DIDescriptor`.
Part of PR23080.

llvm-svn: 235404
diff --git a/llvm/lib/Transforms/Utils/AddDiscriminators.cpp b/llvm/lib/Transforms/Utils/AddDiscriminators.cpp
index dd88f3d..125aab2 100644
--- a/llvm/lib/Transforms/Utils/AddDiscriminators.cpp
+++ b/llvm/lib/Transforms/Utils/AddDiscriminators.cpp
@@ -174,14 +174,14 @@
   for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
     BasicBlock *B = I;
     TerminatorInst *Last = B->getTerminator();
-    DILocation LastDIL = Last->getDebugLoc().get();
+    const MDLocation *LastDIL = Last->getDebugLoc();
     if (!LastDIL)
       continue;
 
     for (unsigned I = 0; I < Last->getNumSuccessors(); ++I) {
       BasicBlock *Succ = Last->getSuccessor(I);
       Instruction *First = Succ->getFirstNonPHIOrDbgOrLifetime();
-      DILocation FirstDIL = First->getDebugLoc().get();
+      const MDLocation *FirstDIL = First->getDebugLoc();
       if (!FirstDIL)
         continue;